Ansible_7

 Variables

Variables can be used in tasks, as well as in template files. we can call variables by "{{ var_name }}"

Quoting in Ansible Strings
A variable right after specifying the module, the YAML parser will misinterpret the variable reference as the beginning of an inline dictionary.


- name: Perform some task
command: {{ myapp }} -a foo

Ansible will try to parse the first part of {{ myapp }} -a foo as a dictionary instead of a string, and will return an error. In this case, you must quote the arguments:
- name: Perform some task
command: "{{ myapp }} -a foo"

A similar problem arises if your argument contains a colon. For example:
- name: Show a debug message
debug:
msg: The debug module will print a message: neat, eh?

The colon in the msg argument trips up the YAML parser.

To get around this, you need to quote the entire msg string. Single and double quotes are both correct; Bas prefers to use double quotes when the string has variables:
- name: Show a debug message
debug:
msg: "The debug module will print a message: neat, eh?"

This will make the YAML parser happy. Ansible supports alternating single and double quotes,
'single quotes' → literal strings
"double quotes" → interpreted strings (supports escaping + special chars)

Double Quotes
- name: Print variable
debug:
msg: "Hello {{ user }}"
👉 {{ user }} will be evaluated

msg: "Line1\nLine2"
👉 Produces:
Line1
Line2


Single Quotes
- name: Print variable
debug:
msg: 'Hello {{ user }}'
👉 Jinja2 still processes it, BUT:
Escaping behaves differently
Harder to nest quotes

msg: 'Line1\nLine2'
👉 Produces:
Line1\nLine2

Loop
A loop executes the task multiple times, each time replacing item with different values from the specified list:
- name: Install multiple packages
hosts: all
tasks:
- name: Install packages
yum:
name: "{{ item }}"
state: present
loop:
- nginx
- git
- curl

Loop with List Variable
vars:
packages:
- nginx
- git
- curl

tasks:
- name: Install packages
yum:
name: "{{ item }}"
state: present
loop: "{{ packages }}"

Loop with Dictionary (Key-Value)
vars:
users:
user1: dev
user2: admin

tasks:
- name: Create users
user:
name: "{{ item.key }}"
comment: "{{ item.value }}"
loop: "{{ users | dict2items }}"
👉 dict2items converts dictionary → list